Which underlined phrase is a prepositional phrase?

What role must the audience play in the creation of an argument? how do bubbles(communities) complicate audience? should audiences be smarter? if yes, how do you make people smarter?

According to the study, what made jonathan swift distrust the assumption most english people of his era made about the superiority of their own race and culture?

What mistakes are there in the sentence sarahas hands were cold and clammy